Gyroscope control



April 1947- F. FISCHER emoscogg CONTROL Filed Nov. 10, 1939 I PatentedApr. 15, 1947 GYROSCOPE CONTROL Franz Fischer, Berlin-Wilmersdorf,Germany vested in the Attorney General of the United v StatesApplicationNovember 10, 1939, Serial No. 303,734

In Germany November 10, 1938 3 Claims. 74-5).

This invention relates to gyroscopes, and more particularly togyroscopic horizons for vehicles such as aircraft.

Devices have heretofore been proposed oi. this character wherein agyroscopic horizon is provided with means which are responsive togravity for imparting stabilizing forces or moments thereto. Such means,for example, pendulums tend to leave their true vertical position whenthe craft upon which they are mounted changes course or speed therebyproducing longitudinal or transverse accelerations. Pendulums underthe-action of these'disturbing accelerations will assume an apparentinstead of a true vertical position. The stabilizing forces which aredependent upon the position 0! the pendulum will consequently have theeffect to move'the plane of the gyroscopic horizon into such a positionthat it is perpendicular to the apparent vertical rather than the truevertical.

One of the objects of the present invention is to provide novel meansfor maintaining a gyroscopic horizon in a plane perpendicular to thetrue vertical.

Another object of the invention is to provide novel means formaintaining a gyroscopic horizon in the true horizontal wherein theeffect of the longitudinal or transverse accelerations of a vehicle uponwhich the novel means are mounted are compensated for.

A further object is to provide novel means for stabilizing a gyroscopichorizon, the directive force of which means is effective at all timesduring the operation 01' the gyroscopic horizon.

Another object is to provide a gyroscopic horizon which is at all timesunder the influence of stabilizing means.

The above and further objects and novel features will more fully appearfrom the detailed description when the same is read in connection withthe accompanying drawings. It is to be expressly understood, however,that the drawings are for purposes of illustration only and are notintended as a definition of the limits of the invention, reference forthis latter purpose being had to the appended claims.

In the drawings, wherein like reference characters refer to like partsthroughout the-several views,

Fig. l is an isometric view partly in section and partly diagrammatic ofone embodiment of the invention;

Fig. 2 is an isometric view partly in section of accelerationcompensating means employed with a second embodiment of the invention;and

Fig. 3 is an isometric view of a gravity responsive stabilizing devicewhich may be employed with the embodiment of Fig, 2.

The forms of the invention illustrated in the accompanying drawings, byway of example,

comprise a. conventional"gyroscopic horizon, apparatus havingstabilizing means which are constituted by means for exerting a turningmoment at a suitable point upon the gyrohorizon, the last named meansbeing a gravity responsive device, for example, a pendulum which governsthe stabilizing force producing means in accordance with departures ofthe gyro horizon from a predetermined relationship with the gravityresponsive device. Novel means are provided for stabilizing the gravityresponsive device and for compensating for the eiTect of disturbingaccelerations thereupon comprising means for measuring accelerationswhich arise in a, direction of oscillation of the gravity responsivedevice. The latter, under the action of the stabilizing the truevertical and thus maintains the horizon in the true horizontal plane. T1

In the foam shown in'F'ig. l-the gyroscopic horizon is constituted by aconventional rotor III which is rotatable on trunnions ii which aremounted for rotation upon an inner gimbal ring l2, the latter beingprovided with trunnions II.

The latter trunnions are conventionally mounted upon an outer gimbalring or frame H which is mounted by means of trunnions [5 upon fixedbearings i6, upon a vehicle such as aircraft. The trunnions l5 areparallel to the transverse axis of the craft, the direction of advanceof the craft being indicated by arrow l1.

The center of gravity of the gyro rotor preterably coincideswith thepoint of intersection of the axes of trunnions l3 and i5.

Suitable stabilizing moment producing means which act directly upon themounting of the gyroscope, and which are controlled by, means which arelater to be explained, comprise a rotary magnet it which includes anarmature i9 which is rigidly connected to an extension of the I tremityof one of the above mentioned oppositely wound exciter windings. Asliding contact 23a is connected by means of a lead 24 through a powersource 25 to a common tapping point of the above mentioned exciterwindings.

Resistance 23 and sliding contact :34 comprise parts of the abovementioned gravity responsive device, the remainder of which isconstituted .by a mounting member 23 for the resistance 23, the memberbeing preferably rigidly connected to one of the trunnions l5. Slidingcontact 23a is rigidly attached to a pendulum 21 which is attached toand mounted for movement with a shaft 23, the latter resting in a fixedbearing 23.

In operation of the apparatus so far described both the windings of thearmature i9 are energized equally in the zero or central position of thesliding contact 230. as shown in Fig. 1. Consequently the oppositelyacting turning moments acting on a trunnion l3 compensate one anotherand no stabilizing force is communicated to the gyro. However, if theplane of rotation of the rotor angularly deviates from the horizontalabout the axes of trunnions l5, the deviation being due, for example, tobearing friction, the mounting member 26 and therewith the resistance 23will anzularly shift, thereby moving the sliding resistance 23a awayfrom its central position upon the resistance. The rotarymagnet i3 willexert a turning moment upon the trunnion l3 which corresponds inmagnitude and direction to the movement of the resistance 23 and slidingmember 23a from the initial position, thereby causing the gym to precessabout the outer gimbal trunnions until the mounting member 23 andtherewith the resistance 23 are restored to their initial centralizedposition. Thus the axis of rotation of the rotor will tend to seek aposition which is parallel to the longitudinal axis of the pendulum, i.e., the apparent vertical.

Novel means are provided for maintaining the pendulum in the truevertical comprising apparatus for measuring, in the embodiment shown,accelerations in the direction of advance, and for exerting acompensating moment upon the pendulum in response to the measuredacceleration. The means are constituted by a rotary magnet 30 having anarmature 3| which is preferably rigidly attached to shaft 23 upon whichthe pendulum is mounted. The armature 3| is provided with a. doublewinding analogous to the one previously mentioned in connection withrotary magnet l3.

The rotary magnet 33 is operatively connected, in a manner to laterappear, with acceleration measuring means comprising a propeller 32which is rotatable by the relative or head wind and which, by means of ashaft 33 which is provided with slip rings 34, rotates a housing member35 which is preferably cylindrical. Rotatably mounted within the housing35 is a shaft 35 upon which is attached a fly wheel 31. Resilient meansare provided causing the shaft 35 to rotate with the housing 35comprising a spring member 33 which is preferably coiled about theshaft, and in a rest position is in the shape of a spiral of Archimedesor a logarithmic curve, as shown in Fig. i. with the inner extremity ofthe spring.

attached to the shaft and the outer extremity of the spring attached tothe housing. Suitable means for damping relative movements of the shaft35 and member 35 are provided comprising an eddy current damperincluding, for example. a cylinder 39 upon shaft 33, the cylinder beingrotatable within a magnet 43.

The operative interconnection of rotary magnet 33 and the accelerationresponsive means comprises a potentiometer device 4| which isconstituted by a resistance 42 which. in the form shown, issemi-circular in shape and in contact with a sliding finger 43, thelatter being rigidly connected to shaft 35, and the resistance beingmounted upon the member 35. The finger 43, by means of the spring 33,lead 44, one of the slip-rings 34, and a lead 45, is connected to thearmature 3|. The opposite extremities of the resistance 42, by means ofsuitable leads, are connected to two of the slip-rings 34 and, by meansof leads 43 and 41, are connected to the positive and negative terminalsof a source of electric energy. Interconnecting these positive andnegative terminals is a resistance 43 to the center of which isconnected a lead 43, the latter being also connected to armature 3|.

In operation the angular speed of shaft 33 is proportional to therelative or head wind and therefore to the air speed of the plane. At aconstant air speed of a plane. 1. e., ata constant speed of thepropeller 32, the housing 35 and the fly wheel 31 are in synchronousrotation and the potentiometer apparatus 4| is in a centralized positionas shown in the drawing. However, if due to an acceleration ordeceleration the speed of the propeller 32 changes, then the housing 35is accelerated or decelerated therewith. Fly wheel 31, due to inertia,continues to rotate temporarily at its previous angular speed and thefinger 43 of the potentiometer is deflected from the central position inresponse to the acceleration or deceleration As a result of the couplingby means of the spring 33, the fly wheel 31 and therewith finger 43 arebrought to the new speed of rotation of the housing 35 and finger 43 isrecentralized.

As long as there exists between the two rotatable members 35 and 31 arelative displacement which is correct in direction, and at leastapproximately correct in magnitude, to the flight acceleration'ordeceleration, then a corresponding relative displacement occurs betweenthe finger 43 and resistance 42 of the potentiometer. The movement offlnger 43 from its central position will cause the rotary magnet 33 toproduce a moment which will compensate or balance the disturbing momentcreated by the acceleration or deceleration of the craft. If the angularspeed of the flywheel 31 becomes equal to that of housing 35, then theflnger 43 returns to a central position and the rotary magnet 33 nolonger receives electric impulses.

A second embodiment of a measuring device for acceleration is shown inF18. 2 wherein a propeller (not shown) is operatively connected adjacentthe armature and rigidly attached to the housing or cylindrical member5| and adapted for rotation therewith. Also mounted upon housing 5| arediametrically opposed brushes 53 which are in contact with aconventional commutator 51. The diametrically opposed brushes areelectrically connected by means of leads 53 and slip-rings 53, therebeing one lead and one slipbodiment no mechanical coupling is employed.

Consequently, in operation there occurs in the event of an accelerationof the housing 5| relative to the shaft 52 an electromagnet brakingaction between the armature 54 and the advancing or lagging poles 55.The poles in this manner exert a torque upon th armature which tends toynchronize the speed of said armature and housing 5|. The current whichis created during the relative rotation of the parts of the generatorcomprises a measure of the angular acceleration of the propeller and isconducted by the commutator, the brushes and connected conductors to theabove mentioned rotary magnet.

A modification of the arrangement of the pendulum device and theinterconnected rotary magnet above described is illustrated in Fig. 3,which is similar to the above mentioned pendulum device with theexception that a resistance 60, which is analogous to the resistance 23,is rigidly mounted upon the aircraft proper rather than mounted upon atrunnion such as'i'i (Fig. 1).

There is thus provided novel means for maintaining the rotor of agyroscopic horizon in a correct and true horizontal position, the meansbeing simple in construction and light in weight. Furthermore, the novelmeans are extremely sensitive but are not easily moved out ofadjustment. The parts for the acceleration measurin apparatus are wellshielded and only such forces act upon the rotating part thereof whichare responsive to the speed and acceleration of the craft.

Although two embodiments of the present invention have been illustratedand described in detail, it is to be expressly understood that theinvention is not limited thereto. For example, instead of employing apropeller to rotate one of the members of the acceleration measuringdevices, it is possible to operatively interconnect one of said membersdirectly to the engine of the aircraft. Also it would be possible tocontrol, e. g., shaft 33 by means of a conventional type of speedometerin such a manner that the speed of said shaft is a function of thespeedof the aircraft. Various changes may be made in the design andarrangement of the parts without departing from the spirit and scope ofthe invention as the same will now be understood by those skilled in theart. For a definition of the limits means, means actuable by electricityfor exerting a stabilizing moment upon the true vertical defining means,a generator including an armature and pole shoes, a flywheel drivablyconnected to the armature, a propeller drivably connected to the poleshoes, and means for electrically connecting the generator and saidmeans actuable by electricity.

2. The combination with a gyro horizon including a gimbal ringsuspension, the horizon being mounted upon a vehicle, of meansfor-exerting a force upon the suspension, means responsive to movementsof the gyro from the true vertical for controlling the first named meansto return the gyro to said true vertical, a flywheel member, a rotatablemember, a propeller operatively connected to the rotatable member, meansfor resiliently interconnecting the flywheel and rotatable member, andmeans for exerting a force upon the second named means in response tochanges from a predetermined angular relation of said members, wherebysaid gyro is prevented from assumin an apparent vertical position duringacceleration and deceleration of the vehicle.

3. In apparatus of the class described, a gyro rotor mounted in a gimbalring suspension adapted to. be carried on an aircraft, means forexerting a turning moment upon the suspension, gravity responsive meansfor governing the firstnamed means, means for exerting a turning momentupon the gravity responsive means, a member rotatable at a speedproportional to the velocity of flight, a fiy wheel resilientlyinterconnected to said member, and means for controlling the momentexerted-upon said gravity responsive mean in response to changes inangular relationship between the member and fly wheel to preventsaidgravityvresponsive means from estab lishing an apparent vertical.

FRANZ FISCHER.

REFERENCES CITED The following references are of record in the file ofthis patent: UNITED STATES "PATENTS Number

